Process of producing fast dyeings on vulcanized fiber and the dyed fiber obtained thereby



Patented Mar. 24, 1942 PROCESS OF PRODUCING FAST DYEINGS N VULCANIZED FIBER. AND THE DYED FIBER OBTAINED THEREBY Josef Niisslein, Frankfort-on-the-Main,

and

Werner Kirst, Konigstein in Taunus, Germany, assignors to General Aniline & Film Corporation, a corporation of Delaware No Drawing. Application October 14, 1939, Serial No. 299,572. In Germany October 10, 1938 6 Claims.

The present invention relates to a process of producing fast dyeings on vulcanized fiber and .tothe dyed fiber obtained thereby.

Colored vulcanized fiber has hitherto been prepared by parchmentizing webs of colored paper or fabrics. The process hasthe drawback that it is limited to such dyestuffs as are not destroyed by the parchmenting process that is to say onlybrown to black shades. which are prepared by the. use of iron oxide or soot can be obtained. The application of organic dyestuffs entails great difilculty since they aredestroyed to alargeextent by the parchmenting process. By dyeing the plates, sheets or shaped bodies of vulcanizedfiber with the substantive or acid dyestufis usually applied in paper dyeing there have been obtained hitherto 'only dyeings whose fastness to water and to rubbing do not comply with the requirements of practice. In most 'cases only the surface of the material is dyed so that, when the material is broken, bent or punched or when its surface is destroyed mechanically, the undyed fiber-appears.

Now, we have found that finished vulcanized fiber may be dyed throughout or'in the grain various tints, by treating sheets, plates or finished articles made from vulcanized fiber with leuco-esters of vat-dyestuffs and producing the vat dyestuif in and on the fiber in known manner by splitting off the ester groups and oxidizing.

The dyeings thus obtained are distinguished by a very good fastness to water and to rubbing having the following formula:

as well as to light.

The following examples serve to illustrate the invention, but they are not intended to limit it thereto:

1. Bleachedvulcanized fiber of 0.5 mm, thic I ness is treated at 70 C. for 2 hours in a bath of the sulfuric acid ester .of the vatdyestufi 3 cc. of ammonia of 25 per cent strength and 5 containing per liter 5 grams of the sodium salt grams of sodium nitrite. The vulcanizedfiber is then introduced into a bath containing 25 cc. of concentrated sulfuric acid per liter of cold water and treated in this bath for l-z'hours. It is then well rinsed and dried. A pink vulcanized fiber is thus obtained which has been dyed throughout and has a very good fastness to water and to light.

2. Bleached vulcanized fiber of 0.5 mm. thick- 'ness is treated at 70 C. for 2 hours ina bath containing per liter 2 grams of the sulfuric acid ester of the vat-dyestuif having the following formula:

and 2 grams of the sulfuric acid ester of dichloro N dihydro l'.2 .l'.2'-- anthraquinoneazine (Schultz Farbstofftabellen, 1931, No. 1234) in the form of their sodium salts, 3 cc. of am monia of 25 per cent strength and 5 grams of sodium nitrite. The vulcanized fiber is then introduced into a bath containing per liter 25 cc. of concentrated sulfuric acid and treated in this bath for 1-2 hours. The material is then rinsed and dried.

' A en vulcanized fiber is thus obtained which has been dyed throughout and has very good properties of fastness.

ed at 70 C. for one; or several hours, according to the thickness of their walls, in a bath; containing per liter 4 grams of the sulfuric acid ester sodium salt of dichloro-N-dihydro-l.2.1'.2'-anthraquinone-azine (Schultz Farbstofitabellen, 193 1, No.

1234) 5 cc. of ammonia and 5 grams ofsodium nitrite. The material is then treated at room temperature for several hours with a solution of 25cc. of concentrated-sulfuric'acid per liter of water, rinsed and dried. I

The dyeing obtained is a vivid blue. According to the duration of .the dyeing operation and development the material is dyed to various depths of penetration. By developing with sulfuric acid 3. Tubes made from vulcanized fiber are treatat raised temperature, somewhat more green dyeings are obtained. a

4. By using in Example 1 instead of the ileumester 4 grams of the sodium salt of the leuoo-ester of the dyestufi'having the following formula:

II /0 Bl a green shade is obtained.-

We claim:

1. Process of producing fast dyeings on vulcanized fiber which comprises applying to the finished vulcanized fiber leuco-esters of vat dyestuffs and producing the vat dyestuflf in and on 20 the fiber by splitting oi! the ester groups and oxi- 2. Process of producing fast blue dyeings on vulcanized fiber which comprises applying to the finished vulcanized fiber the sulfuric acid ester 25 sodium salt of dichloro-N-dihydro-1.2.1'.2'-anthraquinone-azlne and producing the vat dyestuif in and on the fiber by splitting oif the ester groups and oxidizing.

3. Process of producing fast green dyeings on vulcanized fiber which comprises applying to the finishedvulcanizedfiberthesodiumsaltofthe leuco-ester of the dyestuif havingthe following formula: I

o Br 7 as I and producing thevat dyestuif in and on the tained on the fiber by the process claimed in claim 3. I

JOSEF Niissmm. wmrmn'ms'r. 

